Hammerless impact printer

ABSTRACT

A high speed on-the-fly printer having a front wheel with printing character types arranged in predetermined groups mounted for continuous rotation about its axis and for continuous translation along its axis adjacent a sheet of record media on which selected characters are to be printed in a row along the axial direction of translation. Actuating means disposed relative to the paper, traveling axially with the font wheel, causes the font wheel to impact the record media at selected times for printing selected characters in response to input data and font wheel position signals.

' United States Patent 1 Adahan Dec. 16, 1975 1 HAMMERLESS IMPACT PRINTER [75] Inventor: Carmeli Adahan, Berkeley, Calif.

[73] Assignee: The Singer Company, New York,

22 Filed: July 29, 1974 21 Appl. No.: 492,952

[52] U.S. C1 197/55; 267/150 [51] Int. Cl. B41J l/32 [58] Field of Search 196/55, 52; 267/122, 150

[56] References Cited UNITED STATES PATENTS 3,405,793 10/1968 Stoiber 197/55 X 3,630,335 12/1971 Chamness v 197/49 3,760,926 9/1973 Bath 197/55 FOREIGN PATENTS OR APPLICATIONS 841,379 6/1952 Germany 267/122 Primary Examiner-Harland S. Skogquist Attorney, Agent, or FirmJoseph R. Dwyer [57] ABSTRACT A high speed on-the-tly printer having a front wheel with printing character types arranged in predetermined groups mounted for continuous rotation about its axis and for continuous translation along its axis adjacent a sheet of record media on which selected characters are to be printed in a row along the axial direction of translation. Actuating means disposed relative to the paper, traveling axially with the font wheel, causes the font wheel to impact the record media at selected times for printing selected characters in response to input data and font wheel position signals.

6 Claims, 5 Drawing Figures CMNCWENCE A QIRWll' lNPUT DATA US. Patent Dec. 16,1975 Sheet1of2 3,926,295

' 1'2 1 commence Q mm mm om DRIVE CONTROL US. Patent Dec. 16, 1975 Sheet2of2 3,926,295

\NPUT DATA r COWCIDENCE URCUIT DRNE CONTRGL HAMMERLESS IMPACT PRINTER BACKGROUND OF THE INVENTION 1 1. Field of the Invention This invention relates to high-speed on-the-fly impact printing particularly characterized by the font wheel itself being driven to impact the record media to print the selected characters thereon.

2. Prior Art Strip printers wherein successive characters are printed one at a time longitudinally on a relatively long' or endless strip of recordmedia, usually paper, utilize a rotatable font member, such as'a font wheel, on which a set of printing character types are disposed circumferentially about the axis of rotation of the font wheel in the pattern of a helix. A record media strip is advanced intermittently in order to precisely position successive portions of the strip in proper printing orientation with respect to the path of the travel of the font wheel. The font wheel is continuously rotated about its axis, which axis is disposed parallel with the direction of the line or row of the record media on which .the printing is to occur. While the font wheel is continuously rotated about its axis, it is translated or moved axially along its axis in such a manner that, for each one revolution of the font wheel, each character type is brought into printing position adjacent the same spot or location on the record media that is to receive the character impression. The translation of the font wheel axially along its axis is best achieved by means of ascrew having a thread whose pitch is equal to'the pitch of the pattern of the character types on the font wheel. One

example of such translating mechanism is shown anddescribed in detail-in the U.S. Pat. No. 3,406,625 for Driving Means for High-Speed Printing Apparatus by L. D. Chamness et"al., issued Oct. '22, 1968, and an example of the font wheel having helix-like patterns on the periphery is shown and described in detail in U.S. Pat. No. 3,630,335 'for Printing Means With Plural Helical Sets of Type by L. D. Chamness issued Dec.

28, 1971, and an example of the helical type font and the control means therefor for receiving and storing characters indicative ofelectrical signals received from an outside source and to respond to such signals for starting the synchronized rotation of the font wheel and movement of the paper stripshown' and described in U.S. Pat. No. 3,442,364 for Printing System With Helical Arrangement of Type on Type Wheel by R. A.

Ragen, issued May 6, I969.

All the printers of'the type shown in the foregoing patents as well as in other prior art are characterized by the utilization of a print hammer positioned relative to the strip and the font wheel which impacts the strip and drives the latter against the font wheel when the font wheel is in proper printing-orientation with respect to the path of travel of the characters on the font member: 7

To connect the print hammer to the font wheel, there is a link and a hammer carriage which increase the num ber of parts which, in turn, adds to the cost of manufacture and maintenance of the'printer.

This invention, on the other hand, eliminates the print hammer from strip printers by having the font wheel itself impact the strip at the spot or location that is to receive the character impression, thus eliminating the hammer, the hammer carriage, and linkage attendant the print hammer, thus performing the printing function with less parts.

It should be pointed out here, too, that the typewriter type printer having a spherical member for impacting the record media, such as an IBM Selectric typewriter, can be considered a hammerless impact printer but type of printer to which the present invention pertains, i.e., the high-speed on-the-fly type printer differs from the typewriter in its function and use. The typewriter involves high print quality and to accomplish this quality, the aggregate machinery for rotating the sphere about one axis, then tilting the sphere about another axis for character selection, then pivoting and impacting the paper for printing, is complex and also slow in operation, whereas, the on-the-fly printer is high speed, relatively simple, utilizing a continuously rotating print wheel'and electronic controls to perform the function performed by hardware in the typewriter. Actually, the typewriter is too slow or too costly for use as a strip printer where high speed of lesser quality print is acceptable such as in a calculator.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective illustration of a printer in simplified form embodying the teachings of the present invention; I

FIG. 2 is an enlarged view of a portion of the printer shown in FIG. 1 and illustrating the details of a portion of the actuating means for impacting and retracting the font wheel for the printing operation;

FIG. 3 is an elevational view showing an alternative embodiment of an actuating means for impacting and retracting the font wheel for the printing operation;

FIG. 4 is an alternative embodiment of an actuating means for impacting and retracting the font wheel for the printingoperation; and

FIG. 5 is an alternative embodiment in which the resiliency-of the print wheel shaft itself is utilized for the retraction impacting of the font wheel.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 there is shown a high-speed, on-the-fiy, printer indicated-in its entirety as 10 embodying the teachings -of the invention, with electrical control means shown as input data unit 12, coincidence circuit 14, motor control unit 16 and drive control unit 18. The printer 10- includes an electric motor 20 which drives a rotating shaft 22 for continuous rotation when the motor is energized.

A carriage drive screw member 24 is suitably mounted for rotationabout an axis parallel to the axis of the shaft 22. Interconnecting means, such as a toothed belt 26 and toothed pulleys 28 and 30, provide synchronous rotation of the screw member 24 with respect to the rotation of the shaft 22. This screw member 24'isformed with a helical groove 32 having a predetermined pitch.

A- carriage 38 is suitably mounted for reciprocal movementin a path of travel parallel with the axis of rotation of the shaft 22 and screw member 24. The forwardlower portion 40 of the carriage surrounds a portion of the screw member 24 and solenoid actuated carn'age drive pin 42 is mounted in the lower portion of the carriage for reciprocal movement into and out of a portion of the-helical groove 32 that passes through the carriage portion 40. With the screw member 24 rotatingcounter-clockwise about its axis, as indicated direction arrow 44, engagement of the drive pin 42 iii helical groove 32 will cause the @ar'riage to be driveii from 3 right to left as viewed in FIG. 1, which is the normal printing direction.

A biasing means, such as a spring (not shown), normally biases the carriage 38 in the rightward direction. Thus, when the drive pin 42 is retracted from engagement with the groove 32, the carriage will be returned to its rightward or home position.

Mounted on the shaft 22 is a disc-like font wheel 46 having a plurality of character or printing types 48 on the radially outer periphery thereof spaced in patterns as described in more detail in the U.S. Patent to Chamness, No. 3,630,335, supra. The shaft 22 has a longitudinal groove 50 (see FIG. 2 for an enlarged illustration thereof), and a sleeve-like bellows member 52 is suitably secured to one side of the font wheel as by flange 54 and to the shaft 22 by a lug 56 formed at the end of the bellows member opposite to flange 54 and extending into the longitudinal groove 50 so that the shaft, upon rotation by the electric motor 20, drives the font wheel through the bellows member. The font wheel is provided with a centrally located aperture 57, oversize with respect to the shaft, so that the font wheel is loosely coupled to the shaft, yet is slidably axially along the shaft, together with the bellows member 52.

A yoke 58 is secured to the carriage 38 by a pin 60 which also serves as a pivot point for the yoke 58 and engages a narrow groove 62 formed in the bellows member 52. Thus, as the carriage 38 is moved back and forth as described above, the yoke causes a like amount of travel parallel to the axis of rotation of the shaft 22.

A platen 64 is supported on a platform 66 and both are disposed rearwardly (as viewed in FIG. 1) of the font wheel 46. The support platform 66 may be secured to the carriage by appropriate means, such as U-shaped bracket 68 for movement with the carriage, or altematively, platform 66 may be secured to the housing (not shown) for the printer or any suitable stationary member so that either a stationary or movable platen may be selected for use.

An electromagnet 70 is mounted on the carriage 38 in close proximity to the font wheel 46 to magnetically influence the font wheel in such a manner that the font wheel 46 is held coaxial of the shaft out of impact position so that the wheel will not impact against the strip or sheet of paper 72 normally positioned between the font wheel and the platen. Thus, energization of the electromagnet overcomes the resilient bias of the bellows member 52, which normally urges the font wheel into impact with the paper 72, and upon de-energization of the electromagnet the font wheel impacts the paper, and upon re-energization of the electromagnet the resiliency of the bellows will again be overcome to return the font wheel to its position coaxially with the shaft 22.

It will be understood that the electromagnet is suitably connected to the electrical control means 12, 14, 16 and 18, supra, all of which are connected to the character timing or identification wheel 74 which, together with the plurality of induction coils, transmit a set of electrical signals which precisely define and identify the particular character type that is in printing position as the shaft 22 is rotated so that when a charactertype identifying signal matches the character indicative signals from the input data 12, the coincidence circuit 14 detects this fact and the electromagnet 70 is momentarily de-energized, thereby causing printing of the desired character on the strip 72. The electrical control means is more fully described in the U.S. Pat. No.

4 3,630,335 to Chamness, supra, and no further description is deemed necessary herein. Also, a stop means (not shown) is also provided and suitably located on the carriage to prevent impact of the font wheel against the electromagnet 70.

Turning now to FIG. 3, there is shown a second embodiment of the invention in which the bellows 52 of the embodiment shown in FIGS. 1 and 2 has been eliminated. For the sake of clarity, reference numerals utilized in FIGS. 1 and 2 denote similar parts in this embodiment. In this embodiment, a spring 52a is operatively interposed between the carriage 38 and the yoke 59 which pivots about the pivot point 60. De-energization of electromagnet will cause font wheel 46 to impact the strip 72 by allowing the spring 52a to move the yoke 58, and energization of the electromagnet 70 causes a retraction of the font wheel. Thus, the spring 52 performs a function similar to the bellows 52 and is given the same reference numeral but with the suffix a for that reason.

FIG. 4 shows still another embodiment and for the sake of clarity, the same reference numerals are utilized to denote similar parts in this embodiment. However, in this embodiment, the electromagnet 70 is reversed and the pivot point 60b is on the electromagnet 70 rather than on the carriage 38 as in the previous embodiments, but, of course, the entire assembly is located in the carriage (not shown), and the spring 52b perfonns the function of a return spring. In this embodiment, however, the yoke 58 is provided with an extension 76 and, upon energization of the electromagnet 70, the extension 76 is drawn toward the electromagnet, causing the font wheel 46 to impact the strip 72 by the pivoting of the yoke about pivot font 60b. De-activation of the electromagnet 70 would allow the return spring 52b to pull the font wheel from the strip 72 in a manner similar to that described in connection with FIGS. 1 through 3.

Turning now to still another embodiment as shown in FIG. 5. In this embodiment the like parts have again been denoted with like reference numerals of the previous embodiments since they have similar functions in this printer. It is to be noted, however, the shaft 22c of this embodiment not only rotates the font wheel 46 and the carriage 38 and carriage drive mechanisms 26-32, but also performs the functions of the bellows 52 and springs 52a and 52b of the previously described embodiments of FIGS. l-4. In this embodiment, the motor 20 is removed from the side adjacent the font wheel and carriage as shown in FIG. 1 and drives the various mechanisms including the font wheel 46 and the carriage drive mechanisms 26-32 from the opposite side, i.e., adjacent the character timing or identification wheel 74, so that the shaft 220 is cantilevered, as it were. In this embodiment the shaft 22c is flexible and the font wheel 46 is held away from the strip 72 by the energization of the electromagnet 70 which acts against spring 52c. Upon deenergization of the electromagnet 70, the action of the spring 520 causes the font wheel to impact the strip 72. The yoke 58 is secured to the font wheel 46 in any suitable manner, such as by a bearing 78 attached to the font wheel and held by the bifurcation of the yoke. Bearing 78 permits the font wheel to slide along the shaft as the font wheel traverses the strip as the yoke drives the font wheel 46 therewith. The shaft may be provided with an enlarged portion or any other suitable device which will act as a stop so that the bearing 78 and yoke 58 will not slide off the end of the shaft. lt should be noted also, finally, that the shaft 220 and the shaft 24 are shown foreshortened in this embodiment as a matter for expediency, since the cantilever concept of the shaft 52c would obviously require more length than shown in order to properly bend when the font is adjacent the lefthand portion of the strip 72.

What is claimed is:

1. In a high-speed on-the-fly hammerless impact printing apparatus for printing characters on the surface of a sheet of record media comprising:

a rotatable font wheel having character types disposed on the outer periphery thereof; and

means for continually rotating said font wheel about its axis, said axis being substantially parallel with the surface of the record media;

means for moving said font wheel in a path of travel along said axis while said font wheel is being rotated about said axis;

means for urging said font wheel and selected ones of said character types into printing engagement with said record media and retracting same from said printing engagement while said font wheel is being rotated, about and moved along, said axis;

said last-mentioned means comprising an electromagnet located adjacent said font wheel and acting magnetically on the font wheel itself so as to influence the font wheel away from the record media and means which, upon de-energization of the electromagnet, move the font wheel toward the record media.

2. The high-speed on-the-fly hammerless impact printing apparatus as claimed in claim 1 wherein the means for continually rotating said font wheel about its axis comprises:

a shaft; and

bellows means attached to said font wheel and to said shaft to mount said font wheel in rotatable engagement with said shaft.

3. The high-speed on-the-fly hammerless impact printing apparatus as claimed in claim 1 wherein said last mentioned means is resilient means.

4. The high-speed on-the-fly hammerless impact printer as claimed in claim 3 wherein said resilient means comprises a bellows.

5. In a high-speed on-the-fly hammerless impact printer adapted for serially recording selected characters along the print line of a record media comprising:

a carriage adapted for continuous travel along a predetermined print line;

means for moving said carriage in a continuous motion in the direction of the print line;

a rotatable font wheel having character types disposed on the outer periphery thereof;

means for rotating said font wheel as said carriage is continuously traveling along said print line; means on said carriage for urging said font wheel into impact with said record media for printing selected ones of said characters on said record media; and

electromagnetic means acting directly on said font wheel for retracting said font wheel from impact with said record media.

6. The high-speed on-the-fly hammerless impact printer as claimed in claim 5 in which the means for impacting said font wheel comprises resilient means. 

1. In a high-speed on-the-fly hammerless impact printing apparatus for printing characters on the surface of a sheet of record media comprising: a rotatable font wheel having character types disposed on the outer periphery thereof; and means for continually rotating said font wheel about its axis, said axis being substantially parallel with the surface of the record media; means for moving said font wheel in a path of travel along said axiS while said font wheel is being rotated about said axis; means for urging said font wheel and selected ones of said character types into printing engagement with said record media and retracting same from said printing engagement while said font wheel is being rotated, about and moved along, said axis; said last-mentioned means comprising an electromagnet located adjacent said font wheel and acting magnetically on the font wheel itself so as to influence the font wheel away from the record media and means which, upon de-energization of the electromagnet, move the font wheel toward the record media.
 2. The high-speed on-the-fly hammerless impact printing apparatus as claimed in claim 1 wherein the means for continually rotating said font wheel about its axis comprises: a shaft; and bellows means attached to said font wheel and to said shaft to mount said font wheel in rotatable engagement with said shaft.
 3. The high-speed on-the-fly hammerless impact printing apparatus as claimed in claim 1 wherein said last mentioned means is resilient means.
 4. The high-speed on-the-fly hammerless impact printer as claimed in claim 3 wherein said resilient means comprises a bellows.
 5. In a high-speed on-the-fly hammerless impact printer adapted for serially recording selected characters along the print line of a record media comprising: a carriage adapted for continuous travel along a predetermined print line; means for moving said carriage in a continuous motion in the direction of the print line; a rotatable font wheel having character types disposed on the outer periphery thereof; means for rotating said font wheel as said carriage is continuously traveling along said print line; means on said carriage for urging said font wheel into impact with said record media for printing selected ones of said characters on said record media; and electromagnetic means acting directly on said font wheel for retracting said font wheel from impact with said record media.
 6. The high-speed on-the-fly hammerless impact printer as claimed in claim 5 in which the means for impacting said font wheel comprises resilient means. 